1. Field of the Invention
This invention relates to improvements in rail grinding systems for grinding the convex running surface of the track, whether the track be new, worn, relaid, bolted-joint or welded. More specifically, it relates to improvements in rail grinding systems which provide enhanced performance, greater versatility, reduced complexity, fewer operating problems and reduced cost.
While the present invention is described herein with reference to particular embodiments, it should be understood that the invention is not limited thereto. The rail grinding system of the present invention may be employed in a variety of forms and may be adapted to cope with a variety of rail grinding requirements, as those skilled in the art will recognize in the light of the present disclosure.
2. Description of the Prior Art
Rail grinding systems of the general type contemplated herein are well known in the prior art and have received extensive commercial acceptance. Representative prior art includes, for example, U.S. Pat. Nos. 2,018,411 to Miller; 2,035,154 to Faries et al.; 2,197,729 to Miller; 2,779,141 to Speno et al.; and 4,050,196 to Theurer. The present invention is directed to improvements in such systems.
Modern day high train speeds and rail loadings have accentuated the need for track rails having smooth running surfaces for reasons of safety, economy, riding comfort, protection of the track, track bed and rolling stock, noise suppression, over-all reduced maintenance costs, and the like. These considerations are well documented, and the importance thereof has been receiving greater appreciation in recent years. These considerations do not apply just to worn track with bolted rails. Even newly-laid track, which sometimes suffer from minor surface irregularities and joint mismatch, and welded track, which sometimes suffer from irregular or abnormal weld heights, benefit greatly from rail grinding operations to approximate as closely as possible the requisite smooth contour all along the running surface and to minimize impact damage and rail batter and related deleterious effects.
Prior-art rail grinding apparatuses, such as disclosed in the aforementioned patents, suffer from one or more shortcomings which limit their usefulness or otherwise render them costly or otherwise problem-prone. For example, in certain apparatuses the grinding stones must be adjusted to a variety of angles to approximate the running surface of the rail. This necessitates that the grinding stones be tilted and also moved laterally for each new grinding position. The dual adjustment requires coordination of the angle of tilt and lateral displacement, is prone to error when making field adjustments, requires considerable effort, is time-consuming and complicates the apparatus.
Problems are also encountered when adjusting the force or pressure exerted by the grinding stone against the rail head. Manifestly, too little pressure may not provide the results desired and slows down the operation, thereby reducing rail grinding efficiency. Too much pressure may aggravate or make worse the problem intended to be solved and, in addition, may overload or even damage the grinding motors. In adjusting such pressures or forces, some prior art devices have employed multiple hydraulic piston-cylinder assemblies to counterbalance the gravitational forces inherent in the mass of the motor and grinding systems. But it is extremely difficult to balance and coordinate more than one piston-cylinder assembly per grinding stone so as not to tend to cock and lock the apparatus or otherwise jam it so that it is effectively immobilized or hung-up in a non-operative position. This interrupts the rail grinding operation, may cause damage to the apparatus and the track and surrounding area and may otherwise increase costs and reduce efficiency.
Moreover, such prior art systems are expensive and require considerable maintenance. They also lack the versatility provided by the apparatus of the present invention. In some instances, they lack adequate safeguards to protect the system in the event of malfunctions or other failures.